Keywords

Theme: Wet Weather Zone, Percolation Test, Groundwater Test, Wet Weather Groundwater

Description

Abstract

The wet weather zones dataset represents seven zones within Sonoma County. Wet weather zones are geographical areas where rainfall data is collected and tracked for purposes of determining when wet weather percolation testing and ground water observations and can be conducted. Each wet weather zone is unique in its accumulation of rainfall. Depending on your location in the county rainfall will vary. As an example you will see much more rainfall in the Cazadero area then you would see on the Santa Rosa plain due to many factors including microclimate variables, elevation, orientation and slope of terrain, and rain shadow influences. Each zone has a historical rainfall measured in inches that PRMD tracks and uses for the opening of wet weather testing periods for percolation testing and ground water elevation observations.

The "Memorandum of Understanding" with the State of California Regional Water Quality Control Board allows for wet weather percolation groundwater testing between January 1 and March 1, and after having received 50% of the average rainfall for the geographic area.

A property which is located within 2,500 feet of a dividing line between groundwater determination zones is considered to be in either of the zones. This determination can be made by PRMD Well & Septic staff.

The seven Wet Weather Zones and total rainfall amounts required for testing are as follows:
Petaluma, 12.5"
Sonoma, 15"
Santa Rosa, 15"
Sebastopol, 17.5"
Guerneville, 25"
Healdsburg, 20"
Cloverdale, 20"

Purpose

Since the GIS data was developed for planning purposes and use in publication of maps and/or database creation, the data is for illustrative purpose only and is not suitable for parcel specific decision making. 

Therefore, the GIS data presented herein are approximations and further land development determination is at the discretion of the PRMD planning staff which may require a parcel specific site review (to draw parcel specific conclusions).

Supplementary Information

Creation methodology & resources:
1) refer to Data Quality - Attribute Accuracy tab for historical dataset modifications by ActiveMap version release number
2) for ActiveMap Data Capture December 2010 [ver. 2.1], rectified dataset to AM_PARCEL 10/22/2010 (modified to the borders of changed parcels & validated topology)

Dataset consists of (based on selection set of) the following street classes:
Secondary Arterial [A2]
Minor Collector [C2]
Residential [R1]

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Status of the data

Time period for which the data is relevant

Publication Information

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Data storage and access information

Details about this document

Wet Weather Zones

Shapefile